Dainihon Enkaiyochi Zenzu (a map of Japan) (大日本沿海輿地全図)

Dainihon Enkaiyochi Zenzu is a surveyed map of the whole of Japan drawn by Tadataka INO, a geographical surveyor in the late Edo period. It is also called "Ino map." It was completed in 1821.

Details of drawing

This map was drawn based on the survey conducted from 1800 to 1816 as a part of operations of the Edo Bakufu (Japanese feudal government headed by a shogun). Tadataka INO (1745 - 1818), a merchant from Kazusa Province, started to study in earnest after retiring from the business and studied measurement and astronomical observation in Edo under Yoshitoki TAKAHASHI (1764 - 1804) of Tenmonkata (Astronomical Institute) of the Edo Bakufu. In those days there were several theories about the latitudinal length of the earth, argued whether it was 30-ri ("ri" is about 3.927km), 32-ri or 25-ri, and TAKAHASHI and INO aimed to measure this length correctly. Thus TAKAHASHI recommended INO to the Bakufu and asked for permission to measure a degree of the meridian by surveying North Kanto and Tohoku regions on his way to and from Ezochi (inhabited area of Ainu, the present Hokkaido) which he would survey as well because coastal defense had to be strengthened there in case of an advance southward of the Russian Empire. Granted permission, INO, at his own expense, started to survey North Kanto and Tohoku regions as well as Ezochi in his first survey in 1800. Though he had to ask the Bakufu for permission to survey various areas, the Bakufu not only granted him permission but also ordered domains throughout the country to cooperate with him because it determined that his operations were beneficial, perceiving a pressing need for a national coastal map in terms of national defense, with warships of the Western posers frequently witnessed in the sea of Japan.

He surveyed Ezochi and the next year, in 1801, he finished the survey of the east coast of Honshu (the main island of Japan), the west coast of Tohoku region and the coasts of Tokai and Hokuriku regions. In 1804 he put together his past survey results and submitted to the Bakufu a complete map of eastern Japan consisting of 69 large maps, 3 medium-sized maps and a small map (Further information on large, medium-sized and small maps can be found below). The complete map was shown to the seii taishogun (literally, "great general who subdues the barbarians") Ienari TOKUGAWA. As to the length of a degree of the meridian, he calculated it was 28.2-ri (about 110.74km), a quite accurate figure compared even with today's measurements. The top management of the Bakufu was greatly surprised at the high quality of the very accurate and precise maps which were drawn on the basis of local survey unlike the previous maps of Japan and decided to strengthen support for INO's survey operations. INO was officially employed as an officer of Tenmonkata of the Edo Bakufu and his surveys were conducted as operations under direct control of the Bakufu from the fifth survey (in 1805).

Thereafter, INO and his men walked throughout Japan until the tenth survey conducted in 1816 (INO did not participate only in the ninth survey). As to the areas near Soya Subprefecture in the north of Ezochi, he adopted the survey results by Rinzo MAMIYA (1780-1844), his pupil in surveying. INO passed away in 1818 before the map was completed, but his death was hidden and Kageyasu TAKAHASHI (1785 - 1829), a son of his master Yoshitoki TAKAHASHI, led the finishing operation until "Dainihon Enkaiyochi Zenzu" was completed on August 7, 1821. It was submitted to wakadoshiyori (a managerial position in Edo bakufu) along with "Dainihon Enkai Jissokuroku," a record of latitude and survey results throughout Japan.

Characteristics as a map

"Dainihon Enkairyochi Zenzu" was drawn by INO in Edo based on survey results. It is all colored and hand-written, and consists of maps with the following three scales for convenience of use.

Large maps on a scale of 1 to 36,000, 214 sheets in total

They are the most minutely drawn maps. The contour of all the coastlines and continental rivers was drawn in detail from Cape Soya in the north to Yakushima Island in the south, from Kunashiri Island in the east to the Goto Islands in the west. Besides, the names and borders of provinces and counties, the names of feudal lords, villages, the names of temples and rivers, the types of rocky shores and beaches, rice fields and vegetable fields, and salt farms are also on the maps, and not only the coastlines but also map information is shown in detail. However, no lines of latitude and longitude are shown on the large maps.

Medium-sized maps on a scale of 1 to 216,000, 8 sheets in total

For convenience of reduction, data shown on the medium-sized maps, including geographical names, are simplified to some extent compared with those on the large maps, but the lines of latitude and longitude are shown on these maps instead. A meridian which crosses the calendar revision office in Nishisanjo, Kyoto is used as the prime meridian, the basis of longitude, and the lines that cross at right angles to each degree of latitude and longitude are drawn on the basis of actual measured values (Some theories insist that such a method is similar to Sanson projection of the West). However, as INO considered the earth to be a sphere (actually it is not a complete sphere but rather a spheroid), the maps have some errors both in latitude and in longitude. Furthermore, while degrees of latitude are almost correctly measured on the basis of astronomical observation, degrees of longitude are less precise due to a lack of well-developed chronometers required for measurement, and lines of longitude deviate a little eastward from the actual position in marginal areas such as Hokkaido and the south Kyushu.

Small maps on a scale of 1 to 432,000, three sheets in total

They are drawn in half as large a scale as that of the medium-sized maps and encompass all parts of Japan only in three sheets, for the sake of usability. Names of places and other information on the maps are simplified.

Compared with the precision of the depiction of coasts and roadside areas, ridges are depicted in a bird's-eye way just as in traditional Domain Maps and their depiction is not so accurate because height of lands was not surveyed. However, the complete map is precise, detailed and accurate, greatly advanced in terms of technique compared with the past Japanese maps, and almost comparable to Western maps in those days except for some defects.

Siebold Incident

Ino map submitted to Bakufu was secretly kept in Momijiyama Library in the Edo-jo Castle and never disclosed to the public. This is because it was such a detailed map that Bakufu prohibited it from being leaked to the public from a viewpoint of national defense. However, it was revealed that in 1828 Kageyasu TAKAHASHI who was shomotsu bugyo (archive commissioner) taking charge of Momijiyama Library presented Ino map to a doctor working at the Dutch trading house in Nagasaki, Philipp Franz von Siebold (1796-1866) in spite of a ban on possessing the map so Kageyasu TAKAHASHI was arrested and died in prison in March the following year (Siebold Incident). However, expelled from Japan, Siebold published "Map of Japan based on the original map by Japanese and the astronomical observation" by changing Ino map into Mercator projection in Holland in 1840, after he returned home. Precision of the map made some intellectuals in Europe realize Japanese advanced surveying technique.

Ino map in the end of Edo period

In 1861, after the opening of Japan to the world, when the British navy survey ship Acteon tried forcibly to survey the Japanese coast, ignoring the warning by the Bakufu that said it would not be wise to fuel the principle of excluding foreigners, the leader of the ship was much surprised to see a copy of the Ino's small map which the Bakufu officials happened to possess, and agreed to give up the survey project by getting a copy of the map from the Bakufu. Based on the copy of Ino map acquired at that time "Map of Sea along the Coasts of Japan and Korean Peninsula" was published in Britain in 1863, and later it was brought back to Japan and published as "Rough Map of Sea along the Coast of Great Japan"in woodblock printing by Kaishu KATSU (1823-1899) in 1867. As a result of this publication, it had no reason to hide Ino map any longer so Kaisei Gakko (Kaisei School) of the Bakufu published "The Surveyed Map of Japan, official edition" based on the Ino's small maps in that year, too and at last Ino map was disclosed to the public though it was only partially.

Destruction by fire of the original

After the Edo Bakufu collapsed by the Meiji Restoration, Ino map which had been kept by the Bakufu was transferred to the new government. In 1870 Daigaku Nanko (literally, the Southern College of the University), a former Kaisei Gakko, republished "The Surveyed Map of Japan, official edition" and "Dainihon Enkai Jissokuroku" was also published. However, the original of Ino map was burned down at the time of a huge fire at the Imperial Palace in 1873. Thus a duplicate copy which had been kept by the Ino family was dedicated to the government the next year.

Contribution to modern maps

Thanks to this duplicate copy, "The complete map of Japan" was published by the Education Ministry on the basis of the Ino small maps in September 1877, and "Jissoku Kinai Zenzu" (the surveyed map of Kinai) was published by (Japan) Geographical Agency, the Interior Ministry on the basis of medium-sized maps in June 1878. In addition, the said Agency published "Large complete map of Japan" on a scale of 1 to 864,000 on the basis of Ino small and medium-sized maps in 1880. Furthermore, the Ino large and medium-sized maps became the basis of "Geographic map" made by the (Japan) Survey Department, Staff Headquarters of the Imperial Japanese Army (one of the predecessors of Geographical Survey Institute) in 1884. Besides, many jurisdictional maps made by various prefectures were based on the Ino large or medium-sized maps; therefore, the Ino maps made great contributions to administrative maps of modern Japan.

Destruction by fire of the duplicate copy

Later, the duplicate copy of Ino map dedicated by the Ino family was kept at Tokyo University Library, but it was also burned down at the time of the Great Kanto Earthquake in 1923. Ino map (especially large maps) had been long treated as a "Lost Map" since then, and only copies of the medium-sized maps possessed by Tokyo National Museum remained except the copies of about 60 sheets of the total 214 sheets, including a part of the copies kept by The Ino Tadataka Museum in Sawara City (today's Katori City), Chiba Prefecture.

Recent situations

However, 207 sheets of the Ino large maps (169 sheets of which were colorless) were discovered at Library of Congress in the United States in March 2001. It is believed that these maps were replicated as the framework for preparation of Syusei maps on a scale of 1 to 200,000 by the Army as stated above, and taken over and carried to the United States after the World War II.

Of the remaining 7 sheets, two sheets were discovered at National Museum of Japanese History in Sakura City (No.34 Esashi-cho, No.35 Ezo and Okushiri Island, Ezo) and one at National Diet Library (No.107 Shizuoka City, Suruga Province).

As to the other 4 sheets (No.12 Soya, Ezo, No.133 Yamashiro, Kawachi and Settsu Provinces, No.157 Bicchu and Fukuwama City, Bingo Provinces and No. 164 Bingo, Aki and Imabari City, Iyo Provinces), it was discovered in May 2004 that they were included in miniature copies kept by Hydrographic and Oceanographic Department, Japan Coast Guard. They were replicated by the department of navy channel, Empire of Japan (the predecessor of Japan Coast Guard) in the early Meiji period for the purpose of making sea charts. As a result of these discoveries, the whole picture of the 214 sheets of Ino large maps has been figured out. In response, Japan Map Center (administered by Geographical Survey Institute) published "Ino Taizu Soran" (comprehensive list of the Ino large maps) in May 2006 and disclosed Ino map to the public. It is expected that a future study will extend to matters which were difficult to examine, including how Tadataka INO conducted his survey, through detailed examination of the large maps. Considering that colorful replicas including three sheets of high-quality full-sized replicas were discovered at Japan Coast Guard again in January 2007, it is still possible to discover more copies of Ino map in good condition.

Miscellaneous notes

"Yochi" of "Dainihon Enkaiyochi Zenzu" means the earth or the world. It is also called "Kon-yo," comparing the ground to a palanquin on which all things are carried ("Kon" means the world, too). "Kon-yo Bankoku Zenzu" (A Map of the Myriad Countries of the World) by Matteo Ricci (1602) was named in the same manner.

As can be seen from the name "Enkaiyochi Zenzu" this complete map is focused on depiction of the coastlines and has some blank parts as to internal regions because it was made for the operations of the national defense. This complete map is different from "Map of Japan" published by Siebold in Europe in many points, because Siebold depicted internal regions with the help of the map operations by the Edo Bakufu (1645).

A copy of the Ino small maps brought back by the Acteon was possessed by the department of navy channel, the Royal Navy and now is kept at the National Maritime Museum, Greenwich. Greenwich is also a town which Greenwich meridian (0. longitude) crosses.